Brake equalizer



11A. HICKS BRAKE EQUALIZER Filed Dec. 6, 1945 fifa 97 Patented Aug. 14, 14945 UNITED 'STATES ,PATENT oFFlcE BRAKEy EQUALIZER j `James A. Hicks, Atlanta,Ga.; Robert L. Hol-V l brook, administrator of said James A. Hicks, deceased, assignor to A, L. Belle Isle A Application December s, 194.3, serial No. 513,205

` 9 claims. (o1. 18s-'202) The present invention relates to an improved equalizing device for automatically taking up slack and compensating for `wear in a braking system and for controlling the movement or takeup of a brake pedal, and isapplicable to any of the well-known types of brake devices associated with motor vehicles, trains, and the like.

An important object of the invention is to provide simple, eilcient, positive, and economical means whereby the slack developed in a braking system due to the wear of the brake,y shoes, stretching of the brake rigging, increase in the throw or `movement of the foot pedal, wear or distortion of the connecting levers, or other wellknown causes, is automatically taken up.

A further object consists in associating with the piston rod of a brake cylinder, an adjustable member and means operable by the piston, when will become apparent from the following description when taken in conjunction with theaccompanying claims and drawing."

' Referring to the drawing, in which is shown a preferred embodiment of the invention:

Figure 1 is a sectional view taken substantially along the line I--I of Figure 2, and also shows means to effect the expansion of the adjustable member. i f

Figure 2 is a sectional view taken substantially along the line 2-2 of Figure 1.

Figure 3 is a sectional view taken substantially along the line 3--3 of Figure v1.

Figure 4 is an exploded `view of the actuator and the ratchet mechanism.

Figure 5 is a view `substantially similar to i Figure 2 but showing the parts reversed so as to the working stroke of the latter exceeds a predetermined distance, to move the adjustable member axially relative `to the piston rod either to expand the adjustable member or to contract the same in order to take up the slack developed in the braking system. l

A further object comprehends the `provision of a brake equalizer in which an actuator revolubly mounted on the piston rod and axially movable therewith, is operatively associated with a pair of spaced fixed cams and is also operatively connected to an adjustable rod or push bar through a pawl and ratchet mechanism in order to be moved as a unit with the piston rod when the brake is applied and released, and is arranged when slack develops in the braking system to` be actuated by one of the cams during the working stroke of the piston in one direction, and moved in an opposite direction upon the return stroke or .release of the piston to effect the rotation of the ratchet mechanism which imparts axial movement to the adjustable member to expand the same and take up the slack without affecting the normal working stroke of the piston.

A further object consists in associating with the equalizer, reversible or interchangeable means for either expanding the adjustable member relativeto the piston rod or for contracting the same to compensate for wear` or slack developed in the brake mechanism.

A further object is to provide a brake equalizer Other objects and advantages of the invention contract or shorten the adjustable member, and

Figure is a sectional View taken substantially along the line E-S `of Figure 5.

My improved brake equalizer or adjuster is constructed and arranged to be capable of association withan air brake system, a hydraulic brake, or a mechanicalbrake, and may be either directly or indirectly connected to the brake apparatus. As shown, the equalizer is associated with a horizontally disposed air brake cylinder ID which may be connected to the body or chassis of the vehicle through the brackets I I and which may, if desired, be positioned to work vertically.

A reciprocating Vpiston I2 in the cylinder I0 has a piston rod I3,which preferably extends beyond the outer endv of the cylinder and may be composedofthe sections I4 and I5 to provide lan .adjustable member or push bar movable axially relative to the piston rod I3. The section I has at its outer end an elongated slot or recess fI6 which loosely or freely receives the adjacent section I5. The outer end of the section I5 may ybe provided with a headll which bearsagainst an enlarged threaded portion I8 of the arm I9 and kis detachably `connected to the arm by a sleeve or collar 20 having a ange portion 2| confined between the head `I'I and a jam nut 22 on thesection I5. The free end 23 of the arm I9 is as may be desired. Thus it will be seen that the air into the cylinder I0 through the port 24 for` effecting the outward movement of the piston I2 to. apply the brake. A coil spring 25 on the piston rod I3 confined between the piston I2 and the outer end of the cylinder I0, acts normally to Vhas a medial and straight cut-out portion? 32 ilanked on one side by a cam 33 and on the other side by a longitudinally extending arm or side 34. A cam 35 extends inwardly from the plate 28 in a direction opposite to the cam 33 and may have an elongated slot 35 which receives the screws 31 'for adjustably connecting the cam 35 to the plate 28. Manifestly the cam 35 may be formed integral with the plate 28 instead'of being adjustably connected thereto. The plate 28 is preferably provided with a transversely disposed rib 'or projection 38 which is detachably secured thereto by the screws 39 and is arranged to bear against the inner wall of the housing 26 to insure the plate 28 and its associated parts being rmly maintained vin a xed position in the housing.

Revolubly mounted on the piston rod I3 and within the housing 26, is an actuator 4I) which maybe of any suitable configuration and' which, as shown, has an upwardly -projecting lug or larm 4I which extends into the cut-out portion 32 of the plate 28. Also mounted on the piston rod I3 isy a ratchetfwheel Yor member 42` which lhas `its hub 43 extending through the Vhousing 26 and which may also be provided with an annular shoulder 44 (Fig. 4) which abuts against the adjacentfwall of the housing so that when `the parts are assembled, the actuator 48 and the member 42 assume the position shown in Figure 1.

Thevhu-b 43 of the Vmember 42 `is provided with a threaded bore or opening '45 to whichis connected the threaded section I5'of the piston rod. Apawl or dog 46 is releasably connected to the actuator 40 by the bolt or pin 41 and is arranged to be maintained in engagement with a tooth of the ratchet wheel 42 Aby a sprng48 connected at one end to the dog and at its opposite end secured to the actuator.

When the equalizer is associated with an air brake cylinder the parts are normally in the position as shown in Figure l. Upon the brake being applied, air is forced into the cylinder I to move the piston rod I2 and its associated parts outwardly to apply the brake. If no slack or wear into engagement with the cam surface 35 to rotate the actuator 40 in a clockwise direction.

rotated in a counter-clockwise direction or opposite to the direction of movement imparted to has developed in the brake shoes or the'brake equipment, the housing 26 and the actuator 46 move as a unit axially with'the piston rod from the position shown in Figure 2 to the lower edge ofthe cam 35 without affecting the rotation of the actuator 40. This distance, which has previous'ly been determined, comprises the allowable range `of movement of the housing 26 during the normal application of the brake. In the levent the'brakeY shoes` or the brake rigging begin to wear, it will' be seen that upon the application of thebrake, the piston rod I3 will` be moved outwardly a distancevbeyondthe normal throw of theworkng stroke of the piston. When 'this occurs the'lug 4I' 'on the actuator 4'D'is brought it by the cam 35. As the dog 46 is in engagement with a tooth of the ratchet wheel 42 during this return Imovement it will impart a rotative movement to the ratchet in a counterclockwise direction. This movement of the ratchet 42 4by reason of 'the threaded engagement of the same with the section I5 of the piston rod imparts a concomitant axial movement to the section I5 to expand or extend the same relative to the section I4, thus automatically operating to take up slack 'developed in the brake shoe or the brake equipment, without affecting or varying the normal working stroke of the piston I2. The housing 26 is preferably composed of the sectional portions 49 and 50 which may have out` Wardly extending opposed flanges 5I detachably connected by the bolts 52 to permit the removal 'of one'of the sections so as to obtain access to the interior of the housing.

When the equalizer is associated with an air brake, the cams 33 and 35 arespaced the proper rdistance apart so that during the normal working stroke ofthe piston `I 2 thelug 4I on the actuator 40 will not be moved into engagement with the cam 35. The section I5 of the piston rod which also constitutes an adjustable push-bar or member isl connected-to the arm I9 in such a fashion that when the equalizer is initially installed, or at any time thereafter, the section I5 may be readily adjusted relative to the section I3 and the arm I9, upon the loosening of the collar 20 and the applying of a suitable tool or wrench v'to the flat or reduced portion 53 of the rod I'5,`so that the section I5 may be adjusted axially relative to the section I4. When the collar l20 is clamped `or tightened on the arm I9, the section I5 'is firmly connected to the latter and is maintained in a rigid position relativefthereto, During the application of the brake in normal operation, the working stroke of the piston moves the housing 26 and its associated parts outwardly with vthe piston rod I3 'to apply thelbr'ake but does not disturb the actuator y48. As anequalizer is connected to each wheel of the vehicle, andas they working lstroke of each piston is the `same,`a smooth and uniform application ofthe brakes is insu-red; V

The operating'partsoftheequ-alizer are so associated withthepiston rodr I3 as to'be free from any strain or resistancev developed by the movement of the 'piston during its working stroke. Further, when slack occurs the lugylII, upon being brought `into engagement :with "the cam 3'5, oscilflates the actuator `4Il without transmitting any pressure or strain ltothe cams' or the plate 28. On the return 'stroke of the piston the lug 4I is moved-by its engagementwith theV cam v33 and during this" movement, is unopposed'by the cylinder'pressure since the sameha's been previously release-d'. Consequently the parts' ofthe equalizer are not subjected to anyserious strain or resistance which might impair its eiiciency since the only load the actuator 40 and the cam Amechanism 42L have to bear is their own weight.

Thus the life and durability of the equalizer are indefinitely prolonged `In other words, `the equalizer does not operateduring the working stroke of the piston since if` it did it would` have toA oppose or work against the air pressure that actuates the piston rod, which would render it incapable of eiciently carryingA out its function. I

If, for any reason, the parts have to be replaced,

access may be hadto the interior of the housing 2tA upon the removal ofthe section50.

It is essential thatthe working strokesof the pistons associated with the equalizers with which the brake shoes are connected,v be substantially uniform and constant. In other words, anyvariations in the throw of the pistons has a serious eiect on their braking power, eventhoughit be very slight Consequently, if the pistons associated with the wheels do not register the same stroke, it is impossible to obtain equal or uniform application of braking power at the brakes.

- On the other hand, if all of the pistons registhe same degree of stroke isvery important to the efficiency of any air brake mechanism, since it has been found that the number of cubic inches the capacity of a brake cylinderwill change for each increase or decrease of piston travel, is numerically equalto the area of the cylinder. Thus the capacity of an 8 inch cylinder will change 50% cubic inches for every 1 inch change in the piston travel; that of a 10 inch cylinder will change 781/2 cubic inches, and that of a `12 inch cylinder, 113 cubic inches. Y

It may be mentioned that any brake equalizing system wherein the operating parts are arranged to contract or expand against the working pressure of the piston have been found `to be inoperative or inefficient due to the fact that on the application of the brake, the air pressure intro-` duced into the brake -cylinder is such that thev In other words, a ratchet mechanism interposed in an air brake system. for moving one of the members relative to the other during theworking stroke to take up slack through the engagement of a dog with the ratchet `member would be inoperative, since the dog would be incapable of withstanding this `pressure or of lmoving the ratchet wheel` against it. If the present invention, the parts are. so .arranged and associated as to take up the slack on the return stroke of the piston rod, and consequently the equalizer is not subjected ot excessive wear or strain.

Ihe cam is adjustably connected to the plate 28 so that the equalizer may be readily connected to pistons having diierent `working strokes. VThe projection 38 on the plate 28 acts to support rigidly the cams 33 and 35 and prevents these cams and the plate 28 from being moved or dislodged from their xed positions when the actuator and the `ratchet wheel are rotated to take up slack in the brake equipment. As shown in Figure 1, the equalizer is directly connected through theadjusting rod. I5 and the arm |591 to the brake drum of the wheel sothat the-,slack is taken up by reason of the expansion or lengthening of the rod I5. The equalizer may also be efciency `used through an indirect connection with the braking system. to compensate for wear by contracting or shorteningthe section I5 relative to the section I4. In other Words, the equalizer is interchangeable `or reversibleand may be used either to expand .or contract the section rod vI5 without any substantial reorganization of its parts and at a minimum expenditure of time and labor. I Y In the event it is vdesired to use the equalizer to take up slack or compensate for wear, byhaving the adjustable member or section I5contract rather than expand, this may be very ccnveniently done by the simple expedient of reversing the position of the cams 33 and 35 and the pawl 446 so that these parts may assume the position shown in Figures 5 and 6. To make this change, thesection 50 of the housing 26 is removedA to permit access to the actuator 40, and thetnuts v3| arel loosened so that the plate 28 may be turned or reversed. The projection 38 in the meantime has been disconnected from the plate 28 and after the latter is turned, is again secured theretoby the screws 39 so as to assume the position shown in Figure 5 and prevent the plate from rocking or movingduring the actuation of the parts.` l The paw1-46 is withdrawn from the pin 41 and turnedso as to take the position shown in` Figure 6. This rearrangement of the cams and the pawl will,` upon the working stroke of the piston exceeding a predetermined distance, cause the rotation of the actuator 40 which, through its connection with the section I5 of the piston` rod, will move the latter axially and inwardly relative to-the section I II.. Otherwise, the construction and operation of the equalizer is substantially similar tothat previously described.

`Whilefor the purpose of illustrationlthe brake n equalizer has been shown associated with an air brake, it .may with equal efficiency be applied to.

`closer than one inch from the floor board, to` 5()` require the brakes to be manually readjusted.

In order automatically t-o control the movement.

of the brake pedal insuch a hydraulic brake, my

equalizer, without any substantial reorganizationl of itsparts, may be connected through the arm I9 to the brake pedal and the brake drum. "If this is done, the air valve communicating with the cylinder'through the port 24 is cut oiiE and the cams33 and 35 are properly adjusted relative to each other` to take care of the normal throw of the foot pedal and to 'move the actuator 40 when the throw of the pedal exceeds a predetermined distance so as automatically to `take up the slack whichV caused this increased movement to be imparted to the foot pedal. will act to return the parts to their normal position and the housing 26 will move as a unit with. the cylinder I 0. As the operating parts of the equalizer are completely'enclosed within the housing 26, once the adjustable member I5 and the cams 33 and 35 have been properly set, there is little or no danger of these parts being tampered with by an unauthorized party. i l

Further, the equalizer may be also associated with mechanical operating instrumentallties for The spring 25 tak'ing upV the slack in brake systems, such as supplementary levers or the like, so as to impart axial-movement to the piston rod or adjusting bar to either expand or contract the same as may be desired.

LThus it will be seen that av brake equalizer is Yprovidedvwhich by reason of its interchangeabilityof parts may loe-operated either tot expand or contract an adjustable member which connects the piston to the brake drum or any other suitable part of the braking system. Additionally, the equalizer is operated to take up slack or compensate for wear on the return stroke or release of' the'pistonrod so that the equalizer is not subjected to any excessive pressure or resistance.

When the lequalizer is assembled, the housing Zi'may be filled with a suitable lubricant such as dry graphite or the like which will not be detrimentally influenced by climatic changes.

As devices of this character are required to operate in more or less of a restricted area, it will be noted that the compactness of the parts renders the equalizer admirably suited for taking up slack on diierent designs of cars and equipment, and can be readily installed. Further, the equalizer is so constructed that it is capable of withstanding the hard usage and vibrations to which a device of this character is subjected.

It is to be understood that the forms of the invention shown and described are merely illustrative of preferred embodiments, and that such changes may be made as fall within the purview of one skilled in the art without departing from the spirit of the invention and the scope of the appended claims.

. I claim:

vv1;. An equalizing device o-f the class described including a' cylinder, a reciprocating member in said cylinder, `yielclable means to maintain the reciprocating member normally in its inoperative position, an adjustable element connected to the reciprocating member and movable axially relative thereto, a xed plate having a pair of spaced oppositely disposed cams, means for adjusting one of 'the cams longitudinally relative to the other cam, an actuator revolubly mounted o-n the reciprocating member and operatively associated with the spaced cams, and means operatively connecting the actuator to the adjustable element whereby upon the reciprocating member being moved beyond a predetermined distance automatically to rotate said actuator and impart a concomitant axial movement to the adjustable element relative to the reciprocating member;

An equalizing device of the class described. I

including acylinder, a reciprocating piston in saidi cylinder, said piston having a sectional pistori rod,v yieldable means for maintaining the piston in'its normal position, means for' moving the piston outwardly against the' pressure of the yieldable means, one of said sections having a. recess in one endy for receiving the ladjacent threaded end portion of the other section, a housing connected' tothe piston rod so as tobe movable therewith, spaced fixed camsl in said housing, an actuator revolulolyv mounted on the piston rod and having a projection extending intoI the; space between 'the cams so as to4v loev moved in. `one direction by oneA of the cams when'v the piston is moved outwardly beyond a predetermined distance and to b'emoved in anoppositedirectiont by theV other cam uponsthereturn 'stroke -of the piston, and means operatively' c'oniiecting ther actuator' tolv the threaded section' of the piston rodY whereby the movement of the actuator im- 'par-tsa concomitant axial movement to the threaded Vsection relative to the other section of the 'piston rod.y i y An equalizing device of the class described including a cylinder, a reciprocating piston in said-cylinder, said pis-ton having a sectional piston rod,Y yieldable lmeans for maintaining the piston in its normal position, means for moving the piston outwardly against the pressure of'the yieldable means, one of said sections having a |`recess 'in Ione end Vfor receiving the adjacent threaded end portion of the other section, a housing connected to the piston rod so as to be movable therewith, spaced xed cams in said housing,

means to adjust the Vcams to vary the space therebetween, an actuator revolubly mounted on the piston rod and having a projection extending into the space vbetween the `cams so as to be moved in one direction by one of the cams when the piston is moved outwardly beyond a predetermined distance and to be moved in an opposite direction by the other cam upon the return stroke of the pist-on, and means operatively connecting the actuator to the threaded section `of the piston rod whereby the movement of the actuator imparts a concomitant axial movement to the threaded section relative to the 'other section of the piston rod.

fl;Y An Vequalizing device of the class described including 'a cylinder, a reciprocating piston in said cylinder, said piston having a sectional piston rod, one of said sections having a recess in one Aend to receive the adjacent threaded end portion of the other section, va housing connected tothe piston rod so as to be movable therewith, a fixed plate within theA housing provided with spaced cams, said plate having a portion yextending from the housing and connected to the cylinder, an actuator revolubly mounted on the piston rod and having a projection extending into the lspace lbetween the cams so as t-o be moved in one direction by one "of the cams when the piston is moved axially beyond a predetermined distance and to "be moved in an opposite direction by the other cam upon the return stroke of the piston, and means operatively connecting the actuator to the threaded section of the piston whereby upon the piston being moved beyondits predetermined ldistance to cause the axial movement of thethreaded section relative to the other section.

5. An' equalizi'ng 'device vof the class described includingra cylinder, a reciprocating piston in said cylinder, said piston having a sectional piston rod, one of saidsections having a recess in one end to receive the `adjacent threaded end 'portion of the other section, a housing connected to the piston rod so as to be movable therewith, a xed plate within the housing provided with spaced cams, means to prevent movement of the plate relative 4to the cylinder, said plate having Vaportionextending from the housing and connected to the cylinder, an actuator revolubly mounted on the piston rod and having a projection extend-ing into the space'between'the cams 'so as to be moved in one direction kby one of the cams when the piston is moved axially beyond @predetermined distance and to be moved in an opposite direction by the other cam upon the return stroke of the piston, and means operatively connecting the actuator to the threaded section -of the piston whereby upon the piston bei-ng moved beyond its predetermined distance to -causethe laxial movement of 'the 'threaded section relative to the other section.A

6. An equa-lining device of the class described including a cylinder, a reciprocating piston in said cylinder, said piston having a sectional piston rod, one of said sections having a recess in one end to receive the adjacent threaded end portion of the other section, a housing connected to the piston rod so as to be movable therewith, a fixed plate within the housing provided with spaced cams, means on the plate and engaging the housing to insure the cams being maintained in a fixed position, saidplate having a portion extending from the housing and connected to the cylinder, an actuator revolubly mounted on the pistonrod and having a projection extending into the space between the cams so as to be moved in one direction by one of the cams when the piston is moved axially beyond a predetermined distance and to be moved in an opposite direction by the other cam upon the return stroke of the piston, and means operatively connecting the actuator'to the threaded section of the piston whereby upon the piston being moved beyond its predetermined distance to cause the axial move` ment of the threaded section relative to the other section.

7. In a brake equalizing device of the class described, a brake cylinder, a reciprocating piston in said cylinder, saidpiston having a sectional piston rod, one of said sections having'aI nonthreaded recess in one end for receiving the adjacent threaded end portion o'f the other section, a housing connected to the piston rod so as to be axially movable therewith, a fixed plate within the housing provided with spaced cams extending inwardly from opposite sides of the plate, an actuator revolubly mounted on the piston rod and having aprojection extending into the space between the cams so as to be rocked in one direction by one of the cams when the piston rod is moved axially beyond a predetermined distance and to be moved in an opposite direction by the other; cam upon the return of the piston, and

means operatively connecting the actuator to the to said arm and having a flanged portion engagp ing the adjustable bar whereby to rigidly secure the bar to the arm and to permit the adjustment of the bar relative to the rod upon the loosening of the clamping member on the arm.

9. An equalizing device of the class described including a cylinder, a reciprocating member in said cylinder, yieldable means for maintaining the reciprocating member normally in its inoperative position, an adjustable element connected to the reciprocating member, and movable axially relative thereto, spaced i'lxed cams associated with the adjustable element, an actuator revolubly mounted on the reciprocating member and operatively associated with the spaced cams,said camsV and actuator being reversibly mounted in their operative positions, and means operatively connecting the actuator to the adjustable element, the-parts being constructed and arranged so that when the cams and revoluble memberV are mounted in one position and the reciprocating ymember is moved beyond a predetermined distance, it automatically effectsa concomitant axial movement to the adjusting element relative to the reciprocating member to lengthen the adjustable element and when the actuator cams are mounted in a reverse position, the movement of the reciprocating member, shortens the adjustable element relative to the reciprocating member.

i JAMES A. HICKS. 

